Up-conversion fluorescent materials have the characteristics of being chemically stable at room temperature, non-toxic and easily concealed on the products to be protected until excited by infrared light intentionally. It is widely used in high-end anti-counterfeiting fields such as credit cards, bank notes, brand labels, etc.
One of the common methods of making phosphorescent yarns involves coating a layer of fluorescent materials onto the surface of the yarns. However, the fluorescent coating is not sustainable, and the original color of the yarns is also affected.
Therefore, there exists a need for fluorescent yarns with uniformly distributed up-conversion fluorescent material and anti-counterfeiting property.